Answer
$$\tan^{-1}\sqrt{x}+C$$
Work Step by Step
Given
\begin{aligned}
\int \frac{d x}{\sqrt{x}+x \sqrt{x}}
\end{aligned}
Let
$$u^2 =x\ \ \ \to \ \ 2udu=dx$$
then
\begin{aligned}
\int \frac{d x}{\sqrt{x}+x \sqrt{x}}&=\int \frac{2ud u}{\sqrt{u^2}+u^2 \sqrt{u^2}}\\
&= \int \frac{du}{1+u^2}\\
&=\tan^{-1}u+C\\
&=\tan^{-1}\sqrt{x}+C
\end{aligned}